The present invention is a part of tennis net equipment generally, and specifically relates to permanent and portable devices and straps for adjusting and maintaining the regulation height of a tennis net.
Current U.S. Class:473/495; 24/625Intern'l Class:A63B 061/00Field of Search273/29 BA 24/627,628,629,630,631,632,634,635,636References cited:U.S. patent documents:1239924September 1917Lord273/29.1351066August 1920Robinson273/29.1409981March 1920Vaile273/29.1534447April 1925Hardy273/29.3549146December 1970Davis273/29.4247099January 1981Pandak273/29.4671509June 1987Newmann273/29.4831694May 1989Kong 24/635.4973055November 1990Muir273/29.Foreign Patent Documents: 190006December 1922GB273/29. 344615March 1931GB273/29. 516402January 1940GB273/29.2138879October 1984GB 24/634.
A vertical net suspended by a metal cable bisects a tennis court into two equal playing areas. The net and cable are connected to posts that are taller than the regulation height stipulated for the center of the net (currently 36 inches). In preparing the court for play, the cable is pulled taut between the two posts and then a net strap adjusts the center of the net downward to regulation height and attempts to hold it there. The maintenance of the net at the prescribed height is crucial for fair play, with the slightest variance potentially having a profound impact on the scoring and outcome of a given tennis match. Serious players often carry tape measures to matches with them and spend a great amount of time—both prior to and during play—trying to adjust extant net straps to bring the net to the correct height. In professional matches, the net height is checked periodically during a match.
Many forms of net strap exist and a number of different devices have been proposed to correctly measure and maintain a tennis net at the correct height. Muir (U.S. Pat. No. 4,973,055) describes a net strap with an integral measuring system in which two pieces of strapping material are fastened to the court anchor by a double-ended snap hook. One of the straps has a serrated-edge buckle, through which the other strap is fed before it is folded down upon itself and attached to itself by means of hook and loop material. A sliding, interwoven measuring tape device is integral to the net strap and is adequate for measuring the net to the correct height; however, the strap itself does not maintain the net at the correct height over moderate to long periods of time. The buckle system does not sufficiently hold, and the serrated edge in the buckle actively degrades the strap material. Also, the sliding, interwoven measuring tape has a “different look” to it that can be distracting, especially in a professional context.
Pandak (U.S. Pat. No. 4,247,099) offers another net strap with an integral measuring device comprising a single strap passed through a snap hook with a set of interlocking rings or a Velcro fastener close to each end. The strap is passed over the net and the ends secured and the net is at the correct height when one end of the strap touches the ground and an indicator mark is visible on the top of the net. This simple device correctly measures the net height while the strap is new, but the device has two major problems. The free (measuring) end of the strap can abrade and become frayed during match play (thus negating its usefulness in measuring the correct height of the net), and neither the rings nor the Velcro sufficiently holds the strap in place (balls hitting the net loosen the Velcro and cause ring slippage, and dirt, sun, and rain rapidly deteriorate both fasteners' holding ability).
Newman (U.S. Pat. No. 4,671,509) describes a net strap very similar in design to Muir (U.S. Pat. No. 4,973,055), although without the measuring device. Newman's strap is a single piece of material that is joined with a serrated buckle on one end. The other end is fed through the buckle and folded back onto itself where it is attached with a hook and loop material. Unlike Muir's device, however, a sliding snap hook is used for connecting the strap to the court surface, making removal of the strap a tedious process, whereas Muir's can just unclip from the court by disengaging one strap from the double-ended snap clip. The abrasion problems with Muir's serrated buckle occur here as well, though in an even more exacerbated fashion. And this device mandates an exterior measuring device, such as a tape measure or a yardstick be employed. The height of the net must be measured each time it is checked.
Robinson (U.S. Pat. No. 1,351,066) describes a net strap that is limited in use to courts other than hard courts (the majority of courts in the U.S. are hard courts), because it demands an anchoring peg and chain be driven into the court surface. Although once installed (this takes measuring with an exterior measuring device) it remains at the correct height, the strap forces the destruction of existing regulation court anchors (the standard of which are designed to accept a snap clip).
Hardy (U.S. Pat. No. 1,534,447) describes a strap and buckle for holding a tennis net to a prescribed height, but it has no integral measuring system or secondary security systems to prevent slippage.
Vaile (U.S. Pat. No. 1,409,981) describes a center stay for a tennis net which holds the net at 36 inches above the court provided that the court anchor depth never changes from that to which his stay was measured; his device does not allow for what are common deviations in court anchor depths.
Davis (U.S. Pat. No. 3,549,146) shows a measuring device attached to a tennis net strap anchor, but like Robinson, this device must be driven into the court surface (thus it can't be used on hard courts) and cannot be adapted to use the anchors already available on most hard and soft courts.
This self-measuring tennis net strap is unique in many ways and overcomes the problems associated with prior net strap inventions. It is adaptable to different court surfaces and anchor configurations and depths. It is easy to install and adjustable. The cam buckle and primary measuring mark allows for extremely rapid installation and initial adjustment, and the secondary mark confirms the net is set at the right height. The steel tab on the free end of the strap keeps the end from fraying and ensures that the secondary measuring system will work consistently. Should a gross variation occur in the depth of the court anchor, the secondary measuring mark will make for the proper allowance and set the net at the correct height. No other net strap has two effective measuring systems.
This self-measuring tennis net strap also conforms to “traditional” net strap appearances and offers no distraction to players, at the same time that it allows for a player to immediately check to see that the net is indeed maintained at the right height. This strap is extremely durable, with a non-slipping, non-abrading cam buckle, preferably reinforced by two other fastening systems, in order to effect a heavy-duty strap that can withstand high-level play and hard use over long periods of time.